I have 2 test pieces left to do on my MMA course in the UK: open root butt welds in both the flat and the vertical position (mild steel). I'll be using a 3/32" low-hydrogen E7018 rod, and I'd appreciate any advice. I know not to whip a 7018 rod, only to manipulate it in the pool. I'd appreciate suggestions as to the best gap and root face dimensions for both positions (which I assume would be the same for both) and any advice on control of the keyhole etc.